util: Move compare_a_b from user_sort and generalize it.

web/src/settings_users.js

@@ -22,6 +22,7 @@ import * as timerender from "./timerender";
 import * as user_deactivation_ui from "./user_deactivation_ui";
 import * as user_profile from "./user_profile";
 import * as user_sort from "./user_sort";
+import * as util from "./util";
 
 export const active_user_list_dropdown_widget_name = "active_user_list_select_user_role";
 export const deactivated_user_list_dropdown_widget_name = "deactivated_user_list_select_user_role";
@@ -54,7 +55,7 @@ function sort_bot_email(a, b) {
         return (bot.display_email || "").toLowerCase();
     }
 
-    return user_sort.compare_a_b(email(a), email(b));
+    return util.compare_a_b(email(a), email(b));
 }
 
 function sort_bot_owner(a, b) {
@@ -62,11 +63,11 @@ function sort_bot_owner(a, b) {
         return (bot.bot_owner_full_name || "").toLowerCase();
     }
 
-    return user_sort.compare_a_b(owner_name(a), owner_name(b));
+    return util.compare_a_b(owner_name(a), owner_name(b));
 }
 
 function sort_last_active(a, b) {
-    return user_sort.compare_a_b(
+    return util.compare_a_b(
         presence.last_active_date(a.user_id) || 0,
         presence.last_active_date(b.user_id) || 0,
     );

web/src/user_group_components.ts

@@ -5,6 +5,7 @@ import * as people from "./people";
 import type {User} from "./people";
 import type {UserGroup} from "./user_groups";
 import * as user_sort from "./user_sort";
+import * as util from "./util";
 
 export let active_group_id: number | undefined;
 
@@ -77,7 +78,7 @@ export function sort_group_member_email(a: User | UserGroup, b: User | UserGroup
         return 1;
     }
 
-    return user_sort.compare_a_b(a.name.toLowerCase(), b.name.toLowerCase());
+    return util.compare_a_b(a.name.toLowerCase(), b.name.toLowerCase());
 }
 
 export function sort_group_member_name(a: User | UserGroup, b: User | UserGroup): number {
@@ -95,7 +96,7 @@ export function sort_group_member_name(a: User | UserGroup, b: User | UserGroup)
         b_name = b.name;
     }
 
-    return user_sort.compare_a_b(a_name.toLowerCase(), b_name.toLowerCase());
+    return util.compare_a_b(a_name.toLowerCase(), b_name.toLowerCase());
 }
 
 export function build_group_member_matcher(query: string): (member: User | UserGroup) => boolean {

web/src/user_sort.ts

@@ -1,13 +1,5 @@
 import type {User} from "./people";
-
-export function compare_a_b(a: number | string, b: number | string): number {
-    if (a > b) {
-        return 1;
-    } else if (a === b) {
-        return 0;
-    }
-    return -1;
-}
+import {compare_a_b} from "./util";
 
 export function sort_email(a: User, b: User): number {
     const email_a = a.delivery_email;

web/src/util.ts

@@ -488,3 +488,12 @@ export function the<T>(items: T[] | JQuery<T>): T {
     }
     return items[0]!;
 }
+
+export function compare_a_b<T>(a: T, b: T): number {
+    if (a > b) {
+        return 1;
+    } else if (a === b) {
+        return 0;
+    }
+    return -1;
+}

web/tests/util.test.js

@@ -443,3 +443,29 @@ run_test("the", () => {
     // were previously typed wrong but not breaking the app.
     assert.equal(util.the([]), undefined);
 });
+
+run_test("compare_a_b", () => {
+    const user1 = {
+        id: 1,
+        name: "sally",
+    };
+    const user2 = {
+        id: 2,
+        name: "jenny",
+    };
+    const user3 = {
+        id: 3,
+        name: "max",
+    };
+    const user4 = {
+        id: 4,
+        name: "max",
+    };
+    const unsorted = [user2, user1, user4, user3];
+
+    const sorted_by_id = [...unsorted].sort((a, b) => util.compare_a_b(a.id, b.id));
+    assert.deepEqual(sorted_by_id, [user1, user2, user3, user4]);
+
+    const sorted_by_name = [...unsorted].sort((a, b) => util.compare_a_b(a.name, b.name));
+    assert.deepEqual(sorted_by_name, [user2, user4, user3, user1]);
+});